Crime Scene Investigation Case Study
| Crime Scene Investigation | Case Study #1 | | | 1/26/2013 |
OBTAINING and RECORDING PHYSICAL EVIDENCE
When it comes to identifying people that have committed a criminal act, the most positive means is through fingerprints. When we are born, our fingerprints stay with us until we die and our bodies start decomposing. To the human eye our fingerprints look the same, however, further investigation will show that each of us have a unique set of friction ridges that comprise our fingerprints and sets our identity apart from each other. At a crime scene, there are two different types of fingerprints that may be found. Patent prints are visible to the human eye. Latent prints are “unintentional prints found on items of evidence or at a crime scene” (Unknown, Obtaining and Recording Physical Evidence, n.d.). The ability to visualize prints depends on the physical condition of the person who left the print, the surface on which they left it, and the reflection of the light which is used to help visualize the print. Other circumstances that effect the visibility of latent prints is time and exposure to elements like heat and cold. However, in any case, prints should be attempted to be obtained. When latent prints are smudged they lack the specific ridges to distinguish the print correctly. These types of prints may not be perfect for fingerprint analysis; they may be utilized to provide other trace evidence. Before latent prints can be lifted and processed they need to be discovered. Each print left in different types of surfaces have to be processed in a special way. The most common means is with the use of fingerprint powders or through chemical treatment. Most field kits supply a variety of colors so that the powder can contrast with the background on which they were left. The most widely used colors are black and white because they are standard colors that contrast on many objects. Fluorescent fingerprint powders help develop
OBTAINING and RECORDING PHYSICAL EVIDENCE
When it comes to identifying people that have committed a criminal act, the most positive means is through fingerprints. When we are born, our fingerprints stay with us until we die and our bodies start decomposing. To the human eye our fingerprints look the same, however, further investigation will show that each of us have a unique set of friction ridges that comprise our fingerprints and sets our identity apart from each other. At a crime scene, there are two different types of fingerprints that may be found. Patent prints are visible to the human eye. Latent prints are “unintentional prints found on items of evidence or at a crime scene” (Unknown, Obtaining and Recording Physical Evidence, n.d.). The ability to visualize prints depends on the physical condition of the person who left the print, the surface on which they left it, and the reflection of the light which is used to help visualize the print. Other circumstances that effect the visibility of latent prints is time and exposure to elements like heat and cold. However, in any case, prints should be attempted to be obtained. When latent prints are smudged they lack the specific ridges to distinguish the print correctly. These types of prints may not be perfect for fingerprint analysis; they may be utilized to provide other trace evidence. Before latent prints can be lifted and processed they need to be discovered. Each print left in different types of surfaces have to be processed in a special way. The most common means is with the use of fingerprint powders or through chemical treatment. Most field kits supply a variety of colors so that the powder can contrast with the background on which they were left. The most widely used colors are black and white because they are standard colors that contrast on many objects. Fluorescent fingerprint powders help develop
Cited: Coghlan, A. &. (2005). How Far Should Prints be Trusted? New Scientist, 2517(187), 6-7. Retrieved January 21, 2013, from http://search.ebscohost.com.proxy.devry.edu/login.aspx?direct=true&db=a9h&an=18376323&site=ehost-live Lennard, C. (2007, December). Fingerprint Detection: Current Capabilities. Australian Journal of Forensic Science, 39(2), 55-59. Retrieved January 21, 2013, from http://www.informaworld.com Leo, W. (2005, September/October). Will DNA Replace Fingerprints in the 21st Century. The Print, 21(5), 1-5. Retrieved January 21, 2013, from http://www.fingerprintidentification.net/sitebuildercontent/sitebuilderfiles/dnavfingerprints.pdf Spraggs, D. (2007, February 01). How to Lift Fingerprints. Retrieved January 20, 2013, from Police Magazine: www.policemag.com/channel/patrol/articles/2007/02/how-to-lift-fingerprints.aspx Unknown. (n.d., n.d. n.d.). Latent Prints. Retrieved January 21, 2013, from Latent-Prints: http://www.latent-prints.com/Locard.htm Unknown. (n.d., n.d. n.d.). Obtaining and Recording Physical Evidence. Retrieved January 20, 2013, from library.enlisted.info/field-manuals/series-2/FM19_20/CH7.PDF